The conventional fluorescent lamps allow the fluorescent powder to emit visible light by means of the ultraviolet light released in the lamp tube after energized. The common fluorescent lamps include the straight tube fluorescent lamps and the annular fluorescent lamps, wherein the straight tube fluorescent lamps can be designed with varied tube diameters. T5 straight fluorescent lamps have relatively ideal illumination effects to the colorful objects and environments, with a low luminous failure and a long service life, and are suitable for use in the colorful circumstances. In comparison, T8 straight fluorescent lamps have good luminance, save energy, have a long service life, and are suitable for the circumstances with plain colors but high demand to luminance.
In order to further save the energy consumption and ensure the luminance of the illuminating device, the LED lamp tubes are designed on the basis of the conventional fluorescent lamps. The light source of the LED lamp tubes uses a light emitting diode as a light-emitting body, which not only retains the tubular outline of the conventional fluorescent lamp, but also has higher light effect, saves more energy, has a longer service life, and is more environment-friendly. The LED lamp tubes have the same outline, size, and diameter as the conventional fluorescent lamps, and also include for example T5 lamp tubes and T8 lamp tubes. The LED lamp tubes are quite easy to install, and in installation, the original fluorescent lamp is removed, the LED lamp tube is placed, and the ballast and the starter are removed. However, the LED lamp tubes currently used, especially T5 lamp tubes, have to be designed to be externally driven as the space of the lamp tube is not big enough, which not only complicates the structure of the LED lamp tubes, but also increases the manufacture cost of the LED lamp tubes.